SORPTION OF METAL-IONS BY WHOLE CELLS OF BACILLUS AND MICROCOCCUS

Metal removal by seven strains of Bacillus and Micrococcus was investigated. The culture age of the cells had little or no effect on their sorption capacity. Using the Langmuir isotherm, it was possible to determine that Bacillus subtilis ATCC 6633 had the highest maximum sorption capacity for uranium while a Micrococcus sp. strain presented the highest affinity. pH of the solution affected the sorption of uranium, copper, cadmium and zinc by B. subtilis. Hydrochloric acid was effective for desorption of uranium from pre-loaded biomass. The presence of other ion inhibited uranium sorption in the following order: Cu2+>Zn2+>Mg2+>Cd2+>Ca2+>K+.